The field of the invention relates generally to variable frequency (VF) electrical generating systems, and more particularly, to transferring a load between two sources at different frequencies without interrupting power to the load.
At least some known aircraft use VF electrical generating systems as electrical power sources to facilitate improving reliability and minimizing weight. One disadvantage of VF systems is that they cannot easily be placed in parallel with other VF systems or with constant frequency systems to perform a no-break power transfer. Break-type power transfers produce undesirable effects, such as electronic equipment resets and interruptions in power to cabin audio and/or lighting systems, which can distract or annoy passengers. Currently, a no-break transfer between two power sources operating at different frequencies is accomplished by adjusting the output of one source to match the frequency and phase of the other source. However, this configuration requires a relatively complex control system capable of manipulating one or both power sources for the purpose of power transfer and may conflict with other demands on the power source(s).